As pressure sensors, those disclosed in PTL 1 (JP-2009-26495 A) and PTL 2 (JP H4-194638 A) are known.
PTL 1 discloses a pressure sensor including: a housing that is attachable to a member to be attached, which allows a medium to be detected to flow through an inside thereof, in which an introduction hole configured to introduce the medium to be detected is formed; a connector case that has a terminal configured to interchange a signal with an outside, the connector case having a smaller specific heat than the housing; a diaphragm that is displaced in accordance with a pressure to be detected of the medium to be detected which is introduced through the introduction hole; a sensor element that detects the pressure to be detected based on the displacement of the diaphragm; an enclosed space that is formed by assembling the housing and the connector case, the enclosed space having the sensor element arranged therein; and an insulating liquid with which an inside of the enclosed space is filled.
In addition, PTL 2 discloses a pressure sensor including: a diaphragm provided in a case; a pressure detection unit provided inside the case and directed to the diaphragm; and a pressure transmission fluid enclosed between the pressure detection unit and the diaphragm, in which a transmission fluid injection port configured to inject the pressure transmission fluid into the case is formed in the case, and a screw configured to seal the pressure transmission fluid is screwed to this transmission fluid injection port.